CVE-2026-55655

MEDIUMNVD 6.16.1—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.1 under NVD CVSS v3. EPSS exploit probability: 0.1%, top 99% of all CVEs by exploit prediction. GitHub Security Advisory enrichment pending alignment with NVD CVSS.

Triggered by: NVD CVSS baseline
Sources: epss, ghsa, nvd
Trending — 4 sources updated this week
6.1EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.1Exploit: None knownExposed: 0

A fix is available — apply it.

A flaw was found in OpenSSH. A local unprivileged attacker on a Linux client host can hijack client-side X11 forwarding connections. This is possible by pre-binding the preferred abstract X socket name when X11 forwarding is enabled and a local UNIX-domain X socket is used. A successful attack can compromise the confidentiality of forwarded X11 traffic, including sensitive window contents and input, and may allow some manipulation of the forwarded session.

CVSS v3
6.1
EG Score
6.1(medium)
EG Risk
27(Track)
EG Risk 27/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity61% × 45%
Exploitation0% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
1%
KEV
Not listed

Published

June 23, 2026

Last Modified

August 18, 2026

Advisory Details (2)

Auto-updated Jun 23, 2026
Patch available. Sources: redhat.
redhat

2462250 – (CVE-2026-55655) CVE-2026-55655 openssh: Local MITM of X11 forwarding via abstract UNIX socket pre-binding in Red Hat Enterprise Linux OpenSSH client versions

https://bugzilla.redhat.com/show_bug.cgi?id=2462250
redhat Patch Available

cve-details

https://access.redhat.com/security/cve/CVE-2026-55655

Vendor Advisories for CVE-2026-55655(7)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(5)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatrhui5/rhua-rhel9:17865335292026-08-12redhat
redhatopenssh-0:8.0p1-30.el8_102026-07-30redhat
redhatopenssh-0:9.9p1-25.el10_22026-07-30redhat
redhatopenssh-0:9.9p1-9.el9_82026-07-29redhat
redhatopenssh-main-10.3p1-6.hum12026-07-08redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFixed inDependents
openssh1:10.0p1-1 ... 1:9.9p2-2 (86 versions)——
Debian:12(1)
PackageVulnerable rangeFixed inDependents
openssh1:10.0p1-1 ... 1:9.9p2-2 (75 versions)——
Debian:13(1)
PackageVulnerable rangeFixed inDependents
openssh1:10.0p1-7 ... 1:10.4p1-4 (29 versions)——
Debian:14(1)
PackageVulnerable rangeFixed inDependents
openssh1:10.0p1-7 ... 1:10.4p1-4 (25 versions)——

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 22× in last 7d / 95× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 160 total refreshes for this CVE.

  1. 2026-08-19 17:04 UTCEPSS rescore
  2. 2026-08-19 14:17 UTCVendor advisory
  3. 2026-08-19 14:16 UTCGHSA enrichment
  4. 2026-08-18 14:54 UTCEG score recompute
  5. 2026-08-18 14:54 UTCVendor advisory
  6. 2026-08-18 14:54 UTCGHSA enrichment
  7. 2026-08-18 13:48 UTCEPSS rescore
  8. 2026-08-17 13:47 UTCEPSS rescore
  9. 2026-08-17 13:43 UTCVendor advisory
  10. 2026-08-17 13:43 UTCGHSA enrichment
  11. 2026-08-16 14:22 UTCEG score recompute
  12. 2026-08-16 14:22 UTCVendor advisory
  13. 2026-08-16 14:22 UTCGHSA enrichment
  14. 2026-08-16 02:14 UTCEPSS rescore
  15. 2026-08-15 15:00 UTCEG score recompute
  16. 2026-08-15 15:00 UTCVendor advisory
  17. 2026-08-15 15:00 UTCGHSA enrichment
  18. 2026-08-15 01:30 UTCEPSS rescore
  19. 2026-08-14 15:38 UTCVendor advisory
  20. 2026-08-14 15:38 UTCGHSA enrichment
  21. 2026-08-13 16:16 UTCVendor advisory
  22. 2026-08-13 16:16 UTCGHSA enrichment
  23. 2026-08-12 16:36 UTCVendor advisory
  24. 2026-08-12 16:36 UTCGHSA enrichment
  25. 2026-08-12 16:04 UTCVendor advisory
Show 75 more
  1. 2026-08-12 16:04 UTCGHSA enrichment
  2. 2026-08-12 13:08 UTCVendor advisory
  3. 2026-08-12 13:08 UTCGHSA enrichment
  4. 2026-08-11 13:44 UTCEG score recompute
  5. 2026-08-11 13:44 UTCVendor advisory
  6. 2026-08-11 13:44 UTCGHSA enrichment
  7. 2026-08-11 00:00 UTCEPSS rescore
  8. 2026-08-10 14:22 UTCVendor advisory
  9. 2026-08-10 14:22 UTCGHSA enrichment
  10. 2026-08-09 15:00 UTCEG score recompute
  11. 2026-08-09 15:00 UTCVendor advisory
  12. 2026-08-09 15:00 UTCGHSA enrichment
  13. 2026-08-08 16:37 UTCEPSS rescore
  14. 2026-08-08 15:39 UTCEG score recompute
  15. 2026-08-08 15:39 UTCVendor advisory
  16. 2026-08-08 15:39 UTCGHSA enrichment
  17. 2026-08-07 16:16 UTCVendor advisory
  18. 2026-08-07 16:16 UTCGHSA enrichment
  19. 2026-08-06 16:55 UTCEG score recompute
  20. 2026-08-06 16:55 UTCVendor advisory
  21. 2026-08-06 16:55 UTCGHSA enrichment
  22. 2026-08-06 13:47 UTCEPSS rescore
  23. 2026-08-05 19:17 UTCEPSS rescore
  24. 2026-08-05 17:34 UTCVendor advisory
  25. 2026-08-05 17:34 UTCGHSA enrichment
  26. 2026-08-04 15:15 UTCEG score recompute
  27. 2026-08-04 15:15 UTCVendor advisory
  28. 2026-08-04 15:15 UTCGHSA enrichment
  29. 2026-08-04 15:10 UTCEPSS rescore
  30. 2026-08-04 10:39 UTCEPSS rescore
  31. 2026-08-03 10:36 UTCEPSS rescore
  32. 2026-08-03 07:59 UTCVendor advisory
  33. 2026-08-03 07:59 UTCGHSA enrichment
  34. 2026-08-02 07:54 UTCEG score recompute
  35. 2026-08-02 07:54 UTCVendor advisory
  36. 2026-08-02 07:54 UTCGHSA enrichment
  37. 2026-08-02 02:27 UTCEPSS rescore
  38. 2026-08-01 08:32 UTCEG score recompute
  39. 2026-08-01 08:32 UTCVendor advisory
  40. 2026-08-01 08:32 UTCGHSA enrichment
  41. 2026-08-01 04:16 UTCEPSS rescore
  42. 2026-07-31 09:10 UTCEG score recompute
  43. 2026-07-31 09:10 UTCVendor advisory
  44. 2026-07-31 09:10 UTCGHSA enrichment
  45. 2026-07-30 16:28 UTCEPSS rescore
  46. 2026-07-30 09:35 UTCEG score recompute
  47. 2026-07-30 09:35 UTCVendor advisory
  48. 2026-07-30 09:35 UTCGHSA enrichment
  49. 2026-07-30 09:02 UTCVendor advisory
  50. 2026-07-30 09:02 UTCGHSA enrichment
  51. 2026-07-30 06:39 UTCVendor advisory
  52. 2026-07-30 06:39 UTCGHSA enrichment
  53. 2026-07-30 02:40 UTCVendor advisory
  54. 2026-07-30 02:40 UTCGHSA enrichment
  55. 2026-07-29 01:18 UTCEG score recompute
  56. 2026-07-29 01:18 UTCVendor advisory
  57. 2026-07-29 01:18 UTCGHSA enrichment
  58. 2026-07-28 15:37 UTCEPSS rescore
  59. 2026-07-27 17:56 UTCEG score recompute
  60. 2026-07-27 17:56 UTCVendor advisory
  61. 2026-07-27 17:56 UTCGHSA enrichment
  62. 2026-07-26 15:55 UTCEG score recompute
  63. 2026-07-26 15:55 UTCVendor advisory
  64. 2026-07-26 15:55 UTCGHSA enrichment
  65. 2026-07-26 14:54 UTCEPSS rescore
  66. 2026-07-25 14:18 UTCEPSS rescore
  67. 2026-07-24 14:18 UTCEPSS rescore
  68. 2026-07-23 14:18 UTCEPSS rescore
  69. 2026-07-23 03:20 UTCEG score recompute▲ 1.10
  70. 2026-07-22 14:08 UTCEPSS rescore
  71. 2026-07-21 15:25 UTCEPSS rescore
  72. 2026-07-20 17:08 UTCEPSS rescore
  73. 2026-07-18 10:04 UTCEPSS rescore
  74. 2026-07-16 17:03 UTCEPSS rescore
  75. 2026-07-16 13:35 UTCVendor advisory

Frequently asked(5)

What is CVE-2026-55655?
CVE-2026-55655 is a medium vulnerability published on June 23, 2026. A flaw was found in OpenSSH. A local unprivileged attacker on a Linux client host can hijack client-side X11 forwarding connections. This is possible by pre-binding the preferred abstract X socket name when X11 forwarding is enabled and a local UNIX-domain X socket is used. A successful attack can…
When was CVE-2026-55655 disclosed?
CVE-2026-55655 was first published in the National Vulnerability Database on June 23, 2026, with the most recent update on August 18, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-55655 actively exploited?
CVE-2026-55655 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 99.5% of all scored CVEs.
What is the CVSS score of CVE-2026-55655?
CVE-2026-55655 has a CVSS v3 base score of 6.1 (NVD).
How do I remediate CVE-2026-55655?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-55655, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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